Generally, despite that there can be various manufacturing machines used in a factory, any of them can be simply treated as a combination of motors and related transmission systems. Based upon an analysis made by Baldor Electric Company at Year 2001, while considering the cost of electricity used by a motor over its whole working lifetime, it is realized that almost 98% of energy consumed by the motor is wasted, and therefore, it is importance to effectively obtain and control the real-time operating efficiency of all the motors used in the factory so as to be able to gain better energy saving results.
However, facing various motors of different brands and types that can not be stopped for inspection and maintenance at any time and at will, the engineers in charge of energy management in a factory who are generally short of tools for on-line efficiency estimation are not able to obtain the real-time operating conditions of all the motors in the factory, including their electric consumption, operating efficiency and mechanical properties, and thus, the energy management operations are generally performed based upon the experience of the engineers. Currently, for some factories with better energy conservation plans, motors are inspected and maintained in their schedules annual maintenance periods, but for those without good energy conservation plans, the inspection and maintenance operations are only performed during sudden motor malfunctions. Consequently, not only the overall motor operating efficiency is adversely affected, but also the whole production scheduling and planning can be procrastinated. Nevertheless, eventually the factory will suffer higher maintenance cost. Therefore, it is in need of an on-line motor efficiency estimation tool that can be provided to the energy management engineer for obtaining the real-time operating conditions of all the motors in the factory, and thus any motor that is performed poorly and is able to break down can be maintained in time in a preventive manner.
According to most recent market analysis and patent search, there is no similar means or device that is coupled to drivers and is able to display real-time motor efficiency. Primarily, the present disclosure is a motor efficiency analysis method and a device using the method, that both are based on a measured primary current signal and the voltage provided by a driving device for estimating related data at current load, is including rotational speed, torque and stator resistance, etc., by means of several algorithms, and thus to be used in a calculation for obtaining a real-time motor efficiency. Thereby, motors operating in a factory that can not be stopped for inspection and maintenance can be monitored at all time for enabling better motor efficiency management in the factory. In addition, as the motor efficiency analysis method of the present disclosure has innovatively taken the effect of real-time stator resistance Rs variation into the formula, a more accurate efficiency estimation can be achieved. Moreover, since a data register method is adopted for rotation speed estimation, a real-time efficiency is achievable without requiring the use of a powerful core processing ability for performing embedded data processing.